Dead Souls: Book 10 By Ian Rankin

Trouble has a habit of finding John Rebus - and this time it arrives from several directions at once. A paroled murderer is coming home after decades inside. A known paedophile is back on the streets. And the son of a woman from Rebus's past has vanished, with no one else willing to ask the difficult questions. While tracking a suspected poisoner at Edinburgh Zoo, Rebus encounters a man photographing children. Social services insist the activity is legitimate, but Rebus isn't convinced. Should he trust the system and allow the man a second chance, or expose him and risk unleashing mob justice on the city's streets? As tensions rise, Rebus receives a call he can't ignore: a former sweetheart is desperate for help. Her son is missing, and the police are too busy to care. At the same time, the return of a notorious killer at the end of a life sentence stirs up old fears and unfinished business. As these dark strands begin to intertwine, Edinburgh is haunted once again by the consequences of past crimes - and Rebus finds himself at the centre of a mystery that threatens to cost him everything.